nerdexam
Fortinet

NSE4 · Question #561

An administrator wants to create a policy-based IPsec VPN tunnel between two FortiGate devices. Which configuration steps must be performed on both units to support this scenario? (Choose three.)

The correct answer is A. Define the phase 2 parameters. D. Define a route to the remote network over the IPsec tunnel. E. Define the phase 1 parameters, without enabling IPsec interface mode. To create a policy-based IPsec VPN between two FortiGates, both units require matching Phase 1 and Phase 2 parameters, with IPsec interface mode disabled in Phase 1, and a route must be defined to direct traffic over the tunnel.

Submitted by devops_kid· Apr 18, 2026VPN and Routing

Question

An administrator wants to create a policy-based IPsec VPN tunnel between two FortiGate devices. Which configuration steps must be performed on both units to support this scenario? (Choose three.)

Options

  • ADefine the phase 2 parameters.
  • BSet the phase 2 encapsulation method to transport mode.
  • CDefine at least one firewall policy, with the action set to IPsec.
  • DDefine a route to the remote network over the IPsec tunnel.
  • EDefine the phase 1 parameters, without enabling IPsec interface mode.

How the community answered

(32 responses)
  • A
    78% (25)
  • B
    16% (5)
  • C
    6% (2)

Why each option

To create a policy-based IPsec VPN between two FortiGates, both units require matching Phase 1 and Phase 2 parameters, with IPsec interface mode disabled in Phase 1, and a route must be defined to direct traffic over the tunnel.

ADefine the phase 2 parameters.Correct

Phase 2 parameters define the security associations for the data tunnel, including encryption and authentication, which must precisely match on both VPN endpoints to successfully establish and secure the data path.

BSet the phase 2 encapsulation method to transport mode.

Policy-based IPsec VPNs for site-to-site connections typically use tunnel mode encapsulation to encrypt the entire original IP packet, whereas transport mode is generally used for host-to-host or client-specific scenarios.

CDefine at least one firewall policy, with the action set to IPsec.

For policy-based IPsec VPNs, firewall policies define the 'interesting traffic' that triggers the tunnel and have an action like 'ACCEPT'; the action 'IPsec' is specific to route-based VPNs, where it directs traffic to a virtual tunnel interface.

DDefine a route to the remote network over the IPsec tunnel.Correct

A static route must be configured on both FortiGates to direct traffic destined for the remote network specifically over the established IPsec tunnel, ensuring proper traffic flow through the VPN.

EDefine the phase 1 parameters, without enabling IPsec interface mode.Correct

Phase 1 parameters establish the secure control channel (IKE negotiation) and must match on both units; for policy-based VPNs, it is crucial that IPsec interface mode is not enabled, as this setting is exclusive to route-based VPNs.

Concept tested: FortiGate policy-based IPsec VPN configuration

Source: https://docs.fortinet.com/document/fortigate/7.4.0/administration-guide/209971/policy-based-ipsec-vpn

Topics

#IPsec VPN#Policy-based VPN#FortiGate Configuration#Routing

Community Discussion

No community discussion yet for this question.

Full NSE4 Practice